package gov

import (
	"context"
	"encoding/json"
	"fmt"

	gwruntime "github.com/grpc-ecosystem/grpc-gateway/runtime"
	"github.com/spf13/cobra"

	"cosmossdk.io/core/address"
	"cosmossdk.io/core/appmodule"

	"github.com/cosmos/cosmos-sdk/client"
	"github.com/cosmos/cosmos-sdk/codec"
	codectypes "github.com/cosmos/cosmos-sdk/codec/types"
	"github.com/cosmos/cosmos-sdk/testutil/simsx"
	sdk "github.com/cosmos/cosmos-sdk/types"
	"github.com/cosmos/cosmos-sdk/types/module"
	simtypes "github.com/cosmos/cosmos-sdk/types/simulation"
	govclient "github.com/cosmos/cosmos-sdk/x/gov/client"
	"github.com/cosmos/cosmos-sdk/x/gov/client/cli"
	"github.com/cosmos/cosmos-sdk/x/gov/keeper"
	"github.com/cosmos/cosmos-sdk/x/gov/simulation"
	govtypes "github.com/cosmos/cosmos-sdk/x/gov/types"
	v1 "github.com/cosmos/cosmos-sdk/x/gov/types/v1"
	"github.com/cosmos/cosmos-sdk/x/gov/types/v1beta1"
)

const ConsensusVersion = 5

var (
	_ module.AppModuleBasic      = AppModuleBasic{}
	_ module.AppModuleSimulation = AppModule{}
	_ module.HasGenesis          = AppModule{}
	_ module.HasServices         = AppModule{}

	_ appmodule.AppModule     = AppModule{}
	_ appmodule.HasEndBlocker = AppModule{}
)

// AppModuleBasic defines the basic application module used by the gov module.
type AppModuleBasic struct {
	cdc                    codec.Codec
	legacyProposalHandlers []govclient.ProposalHandler // legacy proposal handlers which live in governance cli and rest
	ac                     address.Codec
}

// NewAppModuleBasic creates a new AppModuleBasic object
func NewAppModuleBasic(legacyProposalHandlers []govclient.ProposalHandler) AppModuleBasic {
	return AppModuleBasic{
		legacyProposalHandlers: legacyProposalHandlers,
	}
}

// Name returns the gov module's name.
func (AppModuleBasic) Name() string {
	return govtypes.ModuleName
}

// RegisterLegacyAminoCodec registers the gov module's types for the given codec.
func (AppModuleBasic) RegisterLegacyAminoCodec(cdc *codec.LegacyAmino) {
	v1beta1.RegisterLegacyAminoCodec(cdc)
	v1.RegisterLegacyAminoCodec(cdc)
}

// DefaultGenesis returns default genesis state as raw bytes for the gov
// module.
func (AppModuleBasic) DefaultGenesis(cdc codec.JSONCodec) json.RawMessage {
	return cdc.MustMarshalJSON(v1.DefaultGenesisState())
}

// ValidateGenesis performs genesis state validation for the gov module.
func (AppModuleBasic) ValidateGenesis(cdc codec.JSONCodec, config client.TxEncodingConfig, bz json.RawMessage) error {
	var data v1.GenesisState
	if err := cdc.UnmarshalJSON(bz, &data); err != nil {
		return fmt.Errorf("failed to unmarshal %s genesis state: %w", govtypes.ModuleName, err)
	}

	return v1.ValidateGenesis(&data)
}

// RegisterGRPCGatewayRoutes registers the gRPC Gateway routes for the gov module.
func (AppModuleBasic) RegisterGRPCGatewayRoutes(clientCtx client.Context, mux *gwruntime.ServeMux) {
	if err := v1.RegisterQueryHandlerClient(context.Background(), mux, v1.NewQueryClient(clientCtx)); err != nil {
		panic(err)
	}
	if err := v1beta1.RegisterQueryHandlerClient(context.Background(), mux, v1beta1.NewQueryClient(clientCtx)); err != nil {
		panic(err)
	}
}

// GetTxCmd returns the root tx command for the gov module.
func (ab AppModuleBasic) GetTxCmd() *cobra.Command {
	legacyProposalCLIHandlers := getProposalCLIHandlers(ab.legacyProposalHandlers)

	return cli.NewTxCmd(legacyProposalCLIHandlers)
}

func getProposalCLIHandlers(handlers []govclient.ProposalHandler) []*cobra.Command {
	proposalCLIHandlers := make([]*cobra.Command, 0, len(handlers))
	for _, proposalHandler := range handlers {
		proposalCLIHandlers = append(proposalCLIHandlers, proposalHandler.CLIHandler())
	}
	return proposalCLIHandlers
}

// RegisterInterfaces implements InterfaceModule.RegisterInterfaces
func (AppModuleBasic) RegisterInterfaces(registry codectypes.InterfaceRegistry) {
	v1.RegisterInterfaces(registry)
	v1beta1.RegisterInterfaces(registry)
}

// AppModule implements an application module for the gov module.
type AppModule struct {
	AppModuleBasic

	keeper        *keeper.Keeper
	accountKeeper govtypes.AccountKeeper
	bankKeeper    govtypes.BankKeeper

	// legacySubspace is used solely for migration of x/params managed parameters
	legacySubspace govtypes.ParamSubspace
}

// NewAppModule creates a new AppModule object
func NewAppModule(
	cdc codec.Codec, keeper *keeper.Keeper,
	ak govtypes.AccountKeeper, bk govtypes.BankKeeper, ss govtypes.ParamSubspace,
) AppModule {
	return AppModule{
		AppModuleBasic: AppModuleBasic{cdc: cdc, ac: ak.AddressCodec()},
		keeper:         keeper,
		accountKeeper:  ak,
		bankKeeper:     bk,
		legacySubspace: ss,
	}
}

// IsOnePerModuleType implements the depinject.OnePerModuleType interface.
func (am AppModule) IsOnePerModuleType() {}

// IsAppModule implements the appmodule.AppModule interface.
func (am AppModule) IsAppModule() {}

// RegisterServices registers module services.
func (am AppModule) RegisterServices(cfg module.Configurator) {
	msgServer := keeper.NewMsgServerImpl(am.keeper)
	v1beta1.RegisterMsgServer(cfg.MsgServer(), keeper.NewLegacyMsgServerImpl(am.accountKeeper.GetModuleAddress(govtypes.ModuleName).String(), msgServer))
	v1.RegisterMsgServer(cfg.MsgServer(), msgServer)

	legacyQueryServer := keeper.NewLegacyQueryServer(am.keeper)
	v1beta1.RegisterQueryServer(cfg.QueryServer(), legacyQueryServer)
	v1.RegisterQueryServer(cfg.QueryServer(), keeper.NewQueryServer(am.keeper))

	m := keeper.NewMigrator(am.keeper, am.legacySubspace)
	if err := cfg.RegisterMigration(govtypes.ModuleName, 1, m.Migrate1to2); err != nil {
		panic(fmt.Sprintf("failed to migrate x/gov from version 1 to 2: %v", err))
	}

	if err := cfg.RegisterMigration(govtypes.ModuleName, 2, m.Migrate2to3); err != nil {
		panic(fmt.Sprintf("failed to migrate x/gov from version 2 to 3: %v", err))
	}

	if err := cfg.RegisterMigration(govtypes.ModuleName, 3, m.Migrate3to4); err != nil {
		panic(fmt.Sprintf("failed to migrate x/gov from version 3 to 4: %v", err))
	}

	if err := cfg.RegisterMigration(govtypes.ModuleName, 4, m.Migrate4to5); err != nil {
		panic(fmt.Sprintf("failed to migrate x/gov from version 4 to 5: %v", err))
	}
}

// InitGenesis performs genesis initialization for the gov module. It returns
// no validator updates.
func (am AppModule) InitGenesis(ctx sdk.Context, cdc codec.JSONCodec, data json.RawMessage) {
	var genesisState v1.GenesisState
	cdc.MustUnmarshalJSON(data, &genesisState)
	keeper.InitGenesis(ctx, am.accountKeeper, am.bankKeeper, am.keeper, &genesisState)
}

// ExportGenesis returns the exported genesis state as raw bytes for the gov
// module.
func (am AppModule) ExportGenesis(ctx sdk.Context, cdc codec.JSONCodec) json.RawMessage {
	gs, err := keeper.ExportGenesis(ctx, am.keeper)
	if err != nil {
		panic(err)
	}
	return cdc.MustMarshalJSON(gs)
}

// ConsensusVersion implements AppModule/ConsensusVersion.
func (AppModule) ConsensusVersion() uint64 { return ConsensusVersion }

// EndBlock returns the end blocker for the gov module. It returns no validator
// updates.
func (am AppModule) EndBlock(ctx context.Context) error {
	c := sdk.UnwrapSDKContext(ctx)
	return EndBlocker(c, am.keeper)
}

// AppModuleSimulation functions

// GenerateGenesisState creates a randomized GenState of the gov module.
func (AppModule) GenerateGenesisState(simState *module.SimulationState) {
	simulation.RandomizedGenState(simState)
}

// ProposalContents returns all the gov content functions used to
// simulate governance proposals.
// migrate to ProposalMsgsX. This method is ignored when ProposalMsgsX exists and will be removed in the future.
func (AppModule) ProposalContents(simState module.SimulationState) []simtypes.WeightedProposalContent { //nolint:staticcheck // used for legacy testing
	return simulation.ProposalContents()
}

// ProposalMsgs returns all the gov msgs used to simulate governance proposals.
// migrate to ProposalMsgsX. This method is ignored when ProposalMsgsX exists and will be removed in the future.
func (AppModule) ProposalMsgs(simState module.SimulationState) []simtypes.WeightedProposalMsg {
	return simulation.ProposalMsgs()
}

// RegisterStoreDecoder registers a decoder for gov module's types
func (am AppModule) RegisterStoreDecoder(sdr simtypes.StoreDecoderRegistry) {
	sdr[govtypes.StoreKey] = simtypes.NewStoreDecoderFuncFromCollectionsSchema(am.keeper.Schema)
}

// WeightedOperations returns the all the gov module operations with their respective weights.
// migrate to WeightedOperationsX. This method is ignored when WeightedOperationsX exists and will be removed in the future
func (am AppModule) WeightedOperations(simState module.SimulationState) []simtypes.WeightedOperation {
	return simulation.WeightedOperations(
		simState.AppParams, simState.TxConfig,
		am.accountKeeper, am.bankKeeper, am.keeper,
		simState.ProposalMsgs, simState.LegacyProposalContents,
	)
}

// ProposalMsgsX registers governance proposal messages in the simulation registry.
func (AppModule) ProposalMsgsX(weights simsx.WeightSource, reg simsx.Registry) {
	reg.Add(weights.Get("submit_text_proposal", 5), simulation.TextProposalFactory())
}

// WeightedOperationsX registers weighted gov module operations for simulation.
func (am AppModule) WeightedOperationsX(weights simsx.WeightSource, reg simsx.Registry, proposalMsgIter simsx.WeightedProposalMsgIter,
	legacyProposals []simtypes.WeightedProposalContent, //nolint:staticcheck // used for legacy proposal types
) {
	// submit proposal for each payload message
	for weight, factory := range proposalMsgIter {
		// use a ratio so that we don't flood with gov ops
		reg.Add(weight/25, simulation.MsgSubmitProposalFactory(am.keeper, factory))
	}
	for _, wContent := range legacyProposals {
		reg.Add(weights.Get(wContent.AppParamsKey(), uint32(wContent.DefaultWeight())), simulation.MsgSubmitLegacyProposalFactory(am.keeper, wContent.ContentSimulatorFn()))
	}

	state := simulation.NewSharedState()
	reg.Add(weights.Get("msg_deposit", 100), simulation.MsgDepositFactory(am.keeper, state))
	reg.Add(weights.Get("msg_vote", 67), simulation.MsgVoteFactory(am.keeper, state))
	reg.Add(weights.Get("msg_weighted_vote", 33), simulation.MsgWeightedVoteFactory(am.keeper, state))
	reg.Add(weights.Get("cancel_proposal", 5), simulation.MsgCancelProposalFactory(am.keeper, state))
	reg.Add(weights.Get("legacy_text_proposal", 5), simulation.MsgSubmitLegacyProposalFactory(am.keeper, simulation.SimulateLegacyTextProposalContent))
}
